Anyone know that this plug/wire harness controls? Under engine fuse box.

See pic, it has a broken ground wire. No idea what it controls, but it is factory mounted under the main engine compartment fuse box.

2001 4wd V6 Tacoma.

 

Looks like it's connector EA1, I'm guessing the truck doesn't crank.

Pin 1 (Red) Alternator Ignition Power.
Pin 2 (White) Alternator Voltage Sense.
Pin 3 (Yellow) Alternator Warning Light Control.
Pin 4 (Black/White) Starter Control.

 

That looks pretty accurate..good job on that schematic find

The truck cranks and runs, so not sure how crucial that broken wire is. Going to be a bitch to fix it unless I can buy a new plug with the pigtail off it to splice in.

 

From what I can tell the broken wire is the starter control wire so not sure how it's still cranking unless someone ran a bypass wire.